fix preview when auto-upload is false(#4387)

i18n returns renderSlot (vm._t) function instead i18n.t
https://kazupon.github.io/vue-i18n/en/api.html

* Add optional label to indicator buttons

* Add styling for indicator labels

* Fix positioning of indicators

* Update item.vue

* Update main.vue

* Update carousel.css

* Select: Fix Vuex compability when using multiple

* Adding timeout for first click to allow input event to propagate before second click

* Update select.vue

update docs vue version

* add transfer

* Transfer: add English doc

* Transfer: add tests

* update locale files

default-value sets a default value when picker opens

* i18n: update doc about vue-i18n@6.x

* i18n: fix typo

* 统一使用es6风格的方式引入vue包

* 修正回车换行符处理，以免每次npm run dev 时，index.js都会更改

* 更新编码